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| How
to get an AVA by PISA. |
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| Step
1: Obtain a Zoomed CFD of the AV in the mid Transgastric
or Deep Transgastric view. If there is a sufficiently
stenosed aortic valve, a PISA formation will occur.
The distance from the center of the PISA formation
to it's first aliasing velocity edge (where the color
shifts from blue to red) is the radius of the PISA
formation. |
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| Step
2: Note the aliasing velocity. The aliasing
velocity is the velocity where if the flow exceeds
this velocity the flow will be displayed with colors
from the opposite scale. |
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| Step
3: Obtain a continuous wave doppler (CWD) of the
aortic valve. The CWD of the aortic valve
will yield a flow profile where, utilizing the calipers
(or you can trace it) to show the peak velocity.
The peak velocity is the Vmax which is typically 5
m/sec. |
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| Step 4: Obtain an
angle of the PISA formation: The angle at the aortic valve is
typically 180 degrees, whereas the angle at the mitral valve (for
mitral stenosis calculations) is typically 120 degrees. |
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| Step 5: Determine the LVEF and enter the above data. The degree of aortic stenosis can then be calculated. |
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| Aortic Valve |
Normal Area 2.5-4.5 cm2
Mild Stenosis 1.0-2.5 cm2
Moderate Stenosis 0.75-1.0 cm2
Severe Stenosis < 0.75 cm2 |
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